Fuse



.Fume l, 1943. F. H. DENNER FUSE Filed Jan. 9, 1940 Patented June 1, 1943 UNITED STATES PATENT QFFICE (Granted under the act oi March 3, 1383, as

amended April 30, 1928; 370 0. G. 757) Claims.

The invention described herein may be manu-- factured and used by or for the Government for governmental purposes, 'without the payment to me of any royalty thereon.

This invention relates to a fuse.

In percussion fuses in which a plunger is moved forwardly on impact to function a firing mechanism the situation occurs wherein the impact is of such a character that the force of inertia is not sufcient to move the plunger the requisite distance. p

The purpose of lthis invention is to provide a fuse with a hammer which may operate after the fuse comes to rest, to drive the plunger forwardly and insure functioning of the iiring mechanism.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawing in which:

Fig. 1 is a longitudinal sectional View of a fuse constructed in accordance with the invention and showing the parts in the normal safe'position;

Fig. 2 is a similar fragmentary View showing the hammer in armed position and the plunger partly forward;

Fig. 3 is a view in side elevation with parts in section and showing the hammer held in retracted position.

Referring to the drawing by characters of reference there is shown a hollow fuse casing 5 provided with a front closing plug 5 which retains a fixed firing pin 'I and with a rear closing plug 8 which carries a flash tube 9.

A plunger I0 carrying a primer II and relay charge I2 is disposed between the firing pin 1 and the flash tube 9 which leads to the relay charge 39 and detonatcr All. The rear end of the plunger and the front end of the ash tube are provided respectively with internal threads I3 and I4 for receiving a helical spring I5 which serves to couple these members and which yieldingly opposes forward movement of the plunger on impact. A larger spring I6 seated on the firing pin member 1a and on an external flange I'I of the plunger also serves to hold the plunger away from the firing pin as well as performing a function which will appear hereinafter.

A pair of bolts I8-I8 disposed radially in the casing so as to be operable by centrifugal force are normally held in an inward position by springs I9 with their inner ends in contact with the plunger and in front of an annular flange 20 on the plunger. Each bolt is formed with a peripheral groove 2| adapted, when the bolt is moved outwardly by centrifugal force, to receive a pin 22 which is moved by a spring 23. The pin serves to hold the bolt clear of the plunger so that it cannot return into the path of movement of the plunger after cessation of rotation of the project-ile carrying the fuse.

A hammer 24 in the form of an annular plunger is slidably mounted in the casing, being guided on the flash tube 9. The hammer is normally held in a forward position and against a shoulder 25 (Fig. 2) in the casing by means of a shear pin 26 and a spring 21 which is seated on the rear closing plug 8. The front end 'of the annular hammer is formed with an enlarged bore to overlap and embrace the rear portion of the plunger and in the front end of the hammer there are mounted a pair of radially disposed bolts 28-26 whose inner ends contact the plunger and whose outer ends are each confined by a plug 29. A spring 36 is provided for each bolt 28 for moving it inwardly when centrifugal force has ceased and when the unarmed horizontal relation of the hammer and plunger have changed as occurs when the hammer has moved rearwardly on set-back (Fig. 2), shearing the pin 26 and compressing the spring 27.

The hammer carries a pair of longitudinally disposed latches in the form of flat springs 3 I-3I each secured to the rear part of the hammer by a pin 32 and having its forward part normally bent inwardly and disposed in a slot 33 in the hammer. A weight 34 fixed on the inner side of each spring 3l by means of a rivet 35 is disposed in a recess 3B in the hammer. The head 31 of the rivet bears against the casing when the hammer is in its forward position but when the hammer moves reaiiwardly on set-back it is aligned with an annular groove 33 in the casing. Under the inuence of centrifugal force the fiat spring 3l moves outwardly and the head 3l oi the rivet engages in the groove 38 to hold the hammer in retracted position against the action of spring 2l.

The parts are normally in the safe or unarmed position shown in Fig. l. When the projectile carrying the fuse is fired the force of set-back causes the hammer to move rearwardly to the position shown in Fig. 3, where it is held by engagement of the rivet head 3l in groove 38 of the casing when rotation of the projectile moves the :dat spring 3| outwardly under the influence of centrifugal force. During the period of flight the bolts lB-I S have moved outwardly to release the plunger and they are held by pins 22.

On impact the plunger l 0 moves forwardly due to inertia and drives the primer Il against the ring pin 'l to set olf the charge. However the impact may be of such a character that the force of inertia is not suflicient to drive the plunger all the way home and function the primer. Under this condition, the hammer, which is released from engagement with the casing on cessation of centrifugal force, is driven forwardly by spring 2 and the bolts 28-28 being forced inwardly by their springs (Fig. 3), are in position to strike the rear end of the plunger It and drive it home.

I claim:

1. In a fuse, a casing, a flash tube xed in the rear of the casing, an element of a firing mechanism fixed in the front part of the casing, a plunger having an element of a ring mechanism and yieldingly associated with the flash tube, a spring for holding the plunger in rearward position, centrifugally releasable means for opposing' forward movement of the plunger, a hammer slidable on the flash tube and normally in a forward position, said hammer movable rearwardly on set-back, means for holding the hammer in rearward position during rotation of the fuse, means normally urging the hammer forwardly, and means carried by the hammer for striking the plunger.

2. In a fuse, a casing, a plunger in the casing, means normally holding the plunger in a rearward position against forward movement, a hammer slidable in the casing and normally in 'a forward position overlapping the plunger, said hammer movable rearwardly on set-back to clear the plunger, a helical spring normally urging the hammer forwardly, a fiat spring carried by the hammer and normally held away from the casing, said spring movable by centrifugal force into engagement with the casing to hold the hammer in rearward position against the action of its spring, a bolt in the front overlapping portion of the hammer, means for moving the bolt inwardly in rear of the plunger when the hammer and plunger are longitudinally displaced and when rotation of the fuse has ceased, whereby the bolt will strike the plunger when the hammer is moved forwardly by its spring.

3. In a fuse, a casing, a plunger in the casing, means normally holding the plunger in a rearward position against forward movement, a hammer slidable in the casing and normally in a forward position overlapping the plunger, said hammer movable rearwardly on set-back to clear the plunger, a spring normally urging the hammer forwardly, a normally inoperative latch carried by the hammer and operable by centrifugal force to engage the casing when the hammer is in rearward position, a bolt in the front overlapping portion of the hammer, means for moving the bolt inwardly in rear of the plunger' when the hammer and plunger are longitudinally displaced and when rotation of the fuse has ceased where by the bolt will strike the plunger when the hammer is moved forwardly by its spring.

4. In a fuse, a casing, a plunger in the casing, means normally holdingthe plunger in a rearward position against forward movement, a hammer slidable in the casing and normally in a forward position, said hammer movable rearwardly on set-back, means for holding the hammer in rearward position during rotation of the fuse, means normally urging the hammer forwardly, a bolt in the hammer, means for moving the bolt inwardly in rear of the plunger when the hammer and plunger are longitudinally displaced and when rotation of the fuse has ceased whereby the bolt will strike the plunger when the hammer is moved forwardly.

5. In a fuse, a plunger adapted to move forwardly through inertia on impact, a slidable hammer overlapping the plunger and movable rearwardly on set-back into longitudinally spaced relation with respect to the plunger, means for moving the hammer forwardly, and a driving connecting member between the hammer and plunger, said member carried' by the hammer and normally held in inoperative position by the plunger.

FRANCIS H. DENNER. 

